Ignition system harness



P 19, 1367 R. s. BURDETTE 3,342,168

IGNITION SYSTEM HARNESS Filed March 23, 1965 2 Sheets-Sheet 1 Y4 HmlNVENTOR ROBERT S. BURDETTE BY M1 Alma ATTORNEYS 'Sept. 19,1967

2 Sheets-Sheet Filed March 23, 1965 INVENTOR ROBERT S. BU RDETTE UnitedStates Patent 3,342,168 IGNITION SYSTEM HARNESS Robert S. Burdette, 9Stutz Ave., Mount Vernon, Ohio 43050 Filed Mar. 23, 1965, Ser. No.441,968 2 Claims. (Cl. 123-148) This invention relates to an ignitionsystem for an internal combustion engine, and more particularly to animproved support system for ignition cable harness connecting thedistributor to the engine spark plugs.

Conventional ignition sytems for internal combustion engines, as forexample, in automobiles, include a spark coil whose primary winding isconnected in series with the battery and means repetitively closing andopening breaker points to ground, i.e. for example, the engine block.When the breaker points open, the magnetic field in the primary coilcollapses very rapidly to cause a substantial amount of electricalenergy absorption by a capacitor connected across the breaker points.The rapid collapse of the magnetic field in the primary coil of thespark plug induces a rapidly increasing a nd high potential in thesecondary winding of the spark coil. This action is repeated each timeas the breaker points open and close repetitively, under action of arotating cam.

The oscillating high voltage thus induced in the secondary winding ofthe spark coil is conducted to the rotor of a distributor whichsequentially connects to the various ignition cables leading to thecenter electrodes of the spark plugs in the engine cylinders. The outerelectrodes of the spark plugs are of course grounded, as is one end ofthe spark coil secondary winding, so that the oscillating voltagesapplied sequentially to the spark plugs cause current flow in each sparkplug circuit and produce sparks which jump between the spark plugelectrodes and ignite the vapor in each cylinder in proper sequence asdetermined by the distributor connections.

It is apparent from the above that the peak voltages appliedto eachspark plug must be adequate not only to create an arc across the sparkplug electrodes but an arc of sufiicient intensity to fire the cylinderunder any and all operating conditions of the engine. If the potentialsreceived at different spark plugs are not substantially uniform, thecylinders will not fire in a uniform manner or with equalpower. It is,accordingly, very important that leakage losses due to capacitivereactions of leakage paths from the ignition cable to the enginecomponents be held to a minimum and that the inductive losses from onecable to another also be uniform, so that each spark plug will receive,insofar as possible, an exactly equal potential.

Bearing in mind the above description of conventional ignition systems,it will be readily apparent that conventional ignition cable harnessesand their supports provided on even new automobiles, for example, aresubject to a number of defects. The ignition conductors to the differentcylinders of the same engine are frequently of an unequal length and ofpoor quality having improper resistance characteristics, so that anunequal resistance is provided in the various cables to the flow ofelectric energy from the secondary winding of the spark coil to thedifferent spark plugs; the insulation provided on the ignition cables isoften of poor quality and short life and subject to the development ofcracks and pin holes which increases the leakage currents and rendersthe leakage from one cable different from that of another; the lack ofuniformity of length in the ignition conductors causes a hotter spark insome cylinders than in others; the cables are allowed to touch eachother, thus increasing the leakage, particularly when wet, and therebycausing difierences in the mutual inductances between cables resultingin frequent misfires, or cross-fires, again particularly when theignition cables are wet; the cables are not retained at equal distanceapart along their full lengths, again varying the mutual inductance; theignition cables are not maintained equally spaced from the engine blockyielding unequal leakage losses; in many instances the cables aresharply bent rather than maintained straight or slightly curved, thebends increasing the leakage current losses; and, of primary importance,the cables are infrequently supported along their length and allowed tosag, under stress of wind and fan currents and, particularly, with age,into engagement with metal parts of the engine, thus increasing the highfrequency leakage currents. All of the above defects result in unequalpotentials at the spark plugs of the various cylinders and causeirregularity of firing, uneven engine performance, loss of horsepowerand loss of mileage due to the resultant engine inefiiciency.

It is a primary object of the present invention to provide an improvedignition cable harness and support therefor for an internal combustionengine which will avoid all of the above described defects ofconventional harnesses.

It is another object of the invention to provide an ignition cableharness of high quality conductors having proper specific resistivityand covered by long-lasting, good quality insulating material.

It is a further object of the invention to provide an ignition systemfor internal combustion engines in which the capacitance betweenconductors is held to a minimum and capacitive impedances of leakagepaths between conductors to the engine block are increased to a maximum.

Still another object of the invention is to provide a support system forignition cables in which the mutual inductance between the cables isreduced to a minimum and the mutual inductances between each cable andthe remaining cables of the harness, insofar as practicable, issubstantially equal, so as to equalize the inductive losses in thedifferent cables.

A still further object of the invention is to provide an ignition cableharness for an internal combustion engine in which the cables are ofsubstantially equal length to equalize resistive, inductive andcapacitative losses and in which the cables are firmly supported by anumber of insulated supports adequate to prevent displacement, touchingor sagging of the cables due to wind, fan currents and the like.

Yet a further object of the invention is to provide an ignition cableharness and its support for an internal cornbustion engine which issimple, easy to fabricate and install, and economical, and highlyefficient in operation.

The novel features that are considered characteristic of the inventionare set forth with particularity in the appended claims. The inventionitself, however, both as to its organization and its method ofoperation, together with additional objects and advantages thereof, willbest be understood from the following description of specificembodiments when read in connection with the accompanying drawings,wherein like reference characters indicate like parts throughout theseveral figures and in which:

FIG. 1 is a perspective view from the front of an ignition cable harnessaccording to the invention installed on a V-8 cylinder engine having adistributor located at the front;

FIG. 2 is a plan view of another ignition harness installed on a V-8engine having its distributor located at the rear;

FIG. 3 is a perspective view of a spacer bracket and spacer clip forholding the ignition cables, respectively, spaced from the engine andparallel to each other;

FIG. 4 is a perspective view of another clip similar to that in FIG. 3but having no bracket support;

FIG. 5 is a plan view of another clip adapted to maintain ignitioncables in spaced relation as they cross over one another, particularlyadjacent the distributor;

FIG. 6 is a plan view of still another combined, spacer clip and bracketwhich is adapted to maintain ignition wires spaced parallel but intubular conformation; and

FIG. 7 is an exploded perspective view of one half of an ignitionharness assembled and ready to install on one side of an engine.

Referring now more particularly to the drawings, FIG. 7 shows one halfof a harness according to the invention ready for installation on anS-cylinder engine. Depending upon the physical geometry of the engine,and the location of its distributor and other components, each of thefour cables 10 is cut, preferably, to substantially the same lengthcorresponding to the longest cable required to reach from thedistributor to the furthermost spark plug. Each cable 10 preferablycomprises a resistance conductor of good quality such as glass filamentsimpregnated with a graphite compound having a suitable coefficient ofresistance and covered by a good quality insulator.

Conventional terminals 12, including protective insulating hoods, forsnapping on to the central electrodes of the spark plugs are secured toone end of each cable. The other end of each cable has inserted thereina hair pin shaped spring terminal 14, sharpened to a point at one end.The point is inserted in the end of the cable and makes good contactwith the central conductor. The outside of the hair pin terminaloverlies the insulation at the end of the cable and is insertable into asocket terminal, 34-, FIG. 1, in the distributor 30 for connecting theconductor of the ignition cable to a distributor terminal contact. Thelatter described ends of the cable have surroundmg hoods 16 ofinsulation which, when installed, overlie the openings at the top of thedistributor sockets 34 to prevent entry of water.

In FIGS. 3-6 are shown examples of spacing and holding means forretaining the ignition cables of the harness in desired positions wheninstalled. FIG. 5, for example, illustrates a generally triangularshaped flat clip 22 made of insulating material, such as syntheticplastic, Bakelite, hard rubber, or the like, and having three equallyspaced clamps 24 therein at the corners. The clamps 24 are of a diametersuitable to receive and firmly hold an insulated ignition cable 10*,which must enter through a narrower communicating slot 26 between tworesilient fingers 28. In assembling the clip with the cables, each cableis forced through the slot 26 spreading the fingers 28 until the cablessnap into the larger openings of the clamp 24.

A spacer clip of this nature is useful to prevent the cables fromtouching each other where it is necessary that the cables cross. Forexample, in FIGS. 1 and 2, spacers 22 are shown near the distributors3t) and the spark coil 32. The cables emerging from the distributorhead, because of the firing sequence of the engine cylinders,necessarily must cross in order to connect the appropriate contact inthe distributor with the spark plug in the appropriate cylinder. Thespacers 22 are shown separating and holding the cables near theircrossing points so as to at all times prevent one cable from touchinganother.

In FIG. 4 is shown a spacer clip 40 having four clamps 24 along one edgefor receiving and holding parallel the ignition cables. The clamps aredefined by resilient fingers 28, similar to those in the clip 22 of FIG.5. Clips 40 are also made of synthetic plastic or other insulatingmaterials, like clip 22, and when installed maintain the cables parallelto one another for the most of their length in the runs from thedistributor cap to the spark plugs.

In FIG. 3 a spacer clip 50 similar to clip 40 is illustrated. Clip 50diifers, however, in that a dependent portion 52 provides a socket inwhich is inserted the end of a bracket leg 54 for releasably andfrictionally holding th spacing clip 50 in position. The bracket leg 54is angled with respect to a supporting base leg 56 in which is provideda pair of apertures 58 for mounting screws.

Bracket 54 is preferably made of metal and of any suitable shape orangle and of suitable dimensions for adequately spacing the clip 50 andits supported cables away from an engine block or component metal partsof an engine.

In FIG. 6 is shown a square shaped clip 60 which is provided with wireholding clamps 24 at each corner and defined by resilient fingers 2Sspaced by entry slots 26. The clip 60 is formed of insulating materialsuch as that previously described for clips 22, 40 and 50, and has adependent projection 62 similar to 52 of clip 50 which provides afriction socket for releasably seating a bracket leg 54.

The construction of the ignition cable harness, and its installation,will now be better understood by reference to FIG. 1 in which theharness is shown installed on a V-8 engine 70 with the distributor 30'near the front and a large, cylindrical air cleaner 74 on top. Referringto the left side of the harness the hairpin terminals 14 of the fourignition cables 10 are inserted into the appropriate sockets 34 of thedistributor 30 with the hoods 16 covering the sockets. Where the cablescross over because of the engine cylinder firing sequence, the spacerclip 22 is snapped into holding engagement with the crossing cables. Theclip 22 is disposed as closely to the distributor as possible tominimize and avoid contact between the cables 10. The four cables arethen led in parallel relation around the air cleaner 74 to the center ofthe left rocker arm cover 72, where they are supported spaced from themetal by bracket leg 54 secured by machine screws in the openings 58 ofthe bracket base.

Between the rocker arm cover 72 and the distributor 30, it is desirableto support the cables to prevent them from sagging by attaching them bysuitable spacers to the air cleaner housing 74. To this end additionalbrackets 54 are mounted and spaced about the periphery of the aircleaner housing. Brackets 54' usually are shorter then brackets 54.Brackets 54, 54 and their clips 50 are spaced sufiiciently close toprevent the cables from engaging the engine and its components. Spacerclips 40 are utilized to separate the cables and support the cables inspaced parallel relation at regular intervals between the bracketsupported clips 59 and are spaced sufficiently close to prevent thecables from engaging each other.

The spacing between the clips 40 and 50 may range from 1 /2 to 3 inchesin order to prevent the cables from sagging along their length due toage, wind, fan blown .air currents, and the like. After the cables passthe rocker arm housing 72 they are continued to be spaced by additionalclips 40 until it is necessary to divert the four cables toward theirrespective spark plugs, where their terminals in boots 12 are clipped onto the spark plugs. The right hand side of the ignition harness alsoconsists of four cables spaced and supported in substantially identicalmanner to the left hand side.

In FIG. 2 is shown another 8-cylinder engine of different configuration,lacking an air cleaning housing on the top and in which the distributoris mounted at the rear, the fan belt pulley 82 being shown at the front.The ignition cables 10 are run parallel to each other and prevented fromtouching at the cross over points near the distributor in a similarmanner to the harness shown in FIG. 1. The cross over clips or spacers22 are shown near the distributor, spacers 40 are provided approximatelyevery two inches along the length of the cables and the cables are rundirectly to brackets 54 and then to brackets 54" positioned in thecenters of the rocker arm covers 72'. The brackets 54" are longer anddifferently shaped from brackets 54 so as to hold the cables slightlyabove and spaced outwardly of the rocker arm covers.

It should be apparent from the above description, that harnesses may bepreassembled for each make and model of a car by providing two harnessportions similar to that of FIG. 7, with the harness tailored to thedimensions and accessories of the particular engine for which it isintended to be used. In each harness, care is taken to retain theindividual cables at least one quarter inch apart along their entirelengths by use of the separators or spacers 22, 40 and 50 or 60.

The cables are prevented from sagging due to fan current, winds, age andthe like by spacing the separators in a range of 1 /2 to 3 inches apart,any greater spacing tending to permit the cables to sag into each otheror against a metal engine component. The bracket arms 54, 54 or 54" arealso assembled to the clips 5t] and may be any suitable length and shapeto properly position the cables so that each can be made of equallength, in spite of the positions of the spark plugs to which they areconnected, and to space the cables at least Vs of an inch from the metalof the engine or engine component, which forms an electrical ground forthe ignition circuit.

The above described harness, for each given make and model of engine,may be installed by inserting the appropriate terminals 14 in thedistributor sockets and the caps 12 on the proper spark plugs, eachbracket 54 assembled on the separators 50 then falling in properposition against the meta] supporting component of the engine. Selftapping metal screws are then screwed into the engine component throughopenings 58 to hold the harness securely. The clips 50 with the wiresclamped thereto may be easily removed from their supporting brackets 54,54', 54" to enable removal of the air cleaner 74, rocker arm covers 72,or other parts to which the brackets may be attached.

When thus installed on the engine the leakage losses are reduced to aminimum and the inductive losses betWeen the cables are held equalbecause of the equal spacing. Where sharp bends are essential extraspacers 40 or 22 are assembled to the Wires to prevent the cables fromtouching each other. It should be further apparent that ignition kits asdescribed may be installed either on the engines of new cars at thefactory or may be tailored for later installation on used cars.

Ignition kits fashioned and installed in the manner above described havebeen found to provide very great advantages over the conventional andcommon ignition wire harnesses which are haphazardly run in helterskelter fashion between the distributor and the spark plugs. Forexample, use of ignition kits according to the invention has resulted insubstantial engine horsepower increases, smoother running engines, andlonger service life to the entire ignition system requiring far fewerengine tune ups. In addition, mileage of the vehicle per gallon of gashas increased by at least 10%, and the engines have been found to startmore easily and quickly in cold and wet weather. A considerable savingin time is obtained in changing conventional ignition harness on usedvehicles to effect repair thereof, because on many vehicles the ignitioncable can scarcely be replaced until the engine cools 01f, if replacingcable in the original manner. With the present kit engine the harnesscan be assembled and installed immediately and engine temperature is ofno concern.

Although certain specific embodiments of the invention have been shownand described, it is obvious that many modifications thereof arepossible. The invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

What is claimed is:

1. In an internal combustion engine having a plurality of combustioncylinders, a distributor, a spark plug for each cylinder, an ignitioncable harness including a plurality of cables connecting saiddistributor with the respective spark plugs, and means mounting saidharness on said engine, the improvement wherein said cables are all ofsubstantially equal length to deliver substantially uniform potentialsto each of said spark plugs, and said mounting means comprises aplurality of clips, including a plurality of spacer clips and aplurality of supporting clips, holding said cables spaced apart andsubstantially parallel to one another during their coextensive lengths,with at least two of said cables being substantially coplanar, and forinsulatedly spacing said cables from the metal portions of said engine,said clips being spaced at intervals along the cables a distancesuflicient to prevent said cables from engaging each other during normaloperation of said engine and being formed of a resilient insulatingmaterial and having a plurality of cable holding recesses with entryapertures leading from one edge bordered by curved fingers which admitentry of and releasably grasp the cables, there being at least onespacer clip between each two supporting clips, and brackets mounted onsaid engine between said distributor and said spark plugs and removablysupporting said supporting clips, said brackets being spacedsufliciently to prevent any of said cables from engaging any portion ofsaid engine during normal operation thereof.

2. In an internal combustion engine having a plurality of combustioncylinders, a distributor, a spark plug for each cylinder, an ignitioncable harness including a plurality of cables connecting saiddistributor with the respective spark plugs, and means mounting saidharness on said engine, the improvement wherein said cables are all ofsubstantially equal length to deliver substantially uniform potentialsto each of said spark plugs, and said mounting means comprises aplurality of clips, including a plurality of spacer clips and aplurality of supporting clips, holding said cables spaced apart andsubstantially parallel to one another during their coextensive lengths,with at least two of said cables being substantially coplanar, and forinsulatedly spacing said cables from the metal portions of said engine,said clips being spaced at intervals along the cables a distancesufi'icient to prevent said cables from engaging each other duringnormal operation of said engine and being formed of a resilientinsulating material and having a plurality of cable holding recesseswith entry apertures leading from one edge bordered by curved fingerswhich admit entry of and releasably grasp the cables, and bracketsmounted on said engine between said distributor and said spark plugs andremovably supporting said supporting clips, said brackets being spacedsufficiently to prevent any of said cables from engaging any portion ofsaid engine during normal operation thereof, said clips being spacedalong said cables from a point adjacent the distributor to the portionsof said cables which branch from said harness to the reach portions ofsaid cables for connection to said individual spark plugs, the last ofsaid clips before the branching reach portions being a supporting clip.

References Cited UNITED STATES PATENTS 277,374 5/ 1883 Strohm 174-1461,073,183 9/1913 Trego 123-143 1,089,642 3/1914 Honold 174-154 X1,647,008 10/1927 Lawrence 174-154 2,997,531 8/1961 Oldham et al 174-1583,113,363 12/1963 Fyvie 174-146 FOREIGN PATENTS 786,728 6/ 1935 France.

398,146 1933 Great Britain.

897,151 5/ 1962 Great Britain.

OTHER REFERENCES Cadillac Shop Manual, 1957, pages 9-2.

LAURENCE M. GOODRIDGE, Primary Examiner.

1. IN AN INTERNAL COMBINATION ENGINE HAVING A PLURALITY OF COMBUSTIONCYLIDERS, A DISTRIBUTOR, A SPARK PLUG FOR EACH CYLINDER, AN IGNITIONCABLE HARNESS INCLUDING A PLURALITY OF CABLES CONNECTING SAIDDISTRIBUTOR WITH THE RESPECTIVE SPARK PLUGS, AND MEANS MOUNTING SAIDHARNESS ON SAID ENGINE, THE IMPROVEMENT WHEREIN SAID CABLES ARE ALL OFSUBSTANTIALLY EQUAL LENGTH TO DELIVER SUBSTANTIALLY UNIFORM POTENTIALSTO EACH OF SAID SPARK PLUGS, AND SAID MOUNTING MEANS COMPRISES APLURALITY OF CLIPS, INCLUDING A PLURALITY OF SPACER CLIPS AND APLURALITY OF SUPPORTING CLIPS, HOLDING SAID CABLES SPACED APART ANDSUBSTANTIALLY PARALLEL TO ONE ANOTHER DURING THEIR COEXTENSIVE LENGTHS,WITH AT LEAST TWO OF SAID CABLES BEING SUBSTANTIALLY COPLANAR, AND FORINSULATEDLY SPACING SAID CABLES FROM THE METAL PORTIONS OF SAID ENGINE,SAID CLIPS BEING SPACED AT INTERVALS ALONG THE CABLES A DISTANCESUFFICIENT TO PREVENT SAID CABLES FROM ENGAGING EACH OTHER DURING NORMALOPERATION OF SAID ENGINE AND BEING FORMED OF A RESILIENT INSULATINGMATERIAL AND HAVING A PLURALITY OF CABLE HOLDING RECESSES WITH ENTRYAPERTURES LEADING FROM ONE EDGE BORDERED BY CURVED FINGERS WHICH ADMITENTRY OF AND RELEASABLY GRASP THE CABLES, THERE BEING AT LEAST ONESPACER